Adaptive Cruise Control (ACC) is an evolution of cruise control devices that, in addition to measuring and regulating the forward speed of the vehicle on which the cruise control is mounted (own-car), can also measure the distance to and/or the relative speed of a vehicle ahead of the own-car. The ACC apparatus can permit normal cruise control operation within a range of acceptable conditions. When either the distance or the closing rate with respect to the vehicle ahead becomes unsatisfactory, the ACC can attempt to reduce own-car speed until an acceptable condition range is reestablished. Decreasing own-car speed may require, for example, reducing a throttle setting, canceling cruise control operation, and/or application of own-car brakes. Own-car speed may be allowed to resume if the condition ahead becomes acceptable before cruise control operation is canceled.
ACC can use a sensor technology that transmits a beam, such as an ultrasonic acoustic, infrared optical, or radio frequency electromagnetic signal, in the forward direction with high precision. ACC can also use a directional receiver to detect such a signal. Whether a particular ACC design uses a directional transmitter, a directional receiver, or both, alignment precision can be important to avoiding interpreting traffic in adjacent lanes as being in the own-car lane. Either routine maintenance or repair may require readjustment or verification that the ACC sensor is properly aligned with the own-car longitudinal axis.
Presently-existing test apparatus, such as optical frame alignment tools, are in common use, and can verify that the four corners of a vehicle have been properly realigned after body repairs, as well as to check wheel alignment with respect to the vehicle structure. It is possible to use an optical frame alignment tool to determine the fore-and-aft axis of a vehicle starting at some point on the front of the vehicle, but this is not the complete measurement required for ACC alignment, and converting such an axis determination to the required alignment test is cumbersome to perform and affords marginal accuracy.
Accordingly, it would be desirable to provide a method and apparatus that aids in mechanically aligning and verifying the alignment of adaptive cruise control sensors.